Which metals make up stainless steel? | Reference.com Which metals make up stainless steel? A: Quick Answer Stainless steel is a special form of steel that is made of chromium added to steel. Regular steel is an alloy that is made of both iron and carbon. There are different types of stainless steel depending on how much chromium is added and if there are any other elements added in small amounts like nickel. Stainless Steel - General Information - Alloying Elements in Stainless Steel Stainless Steel - General Information - Alloying Elements in Stainless Steel Alloying Elements in Stainless Steel Stainless Steels comprise a number of alloying elements according to the specific grade and composition. Listed below are the alloying additions with the reason for their presence, whilst attched is a summary table. Carbon (C): Iron is alloyed with carbon lo make steel and has the effect of increasing the hardness and strength of iron. Pure iron cannot be hardened or strengthened by heat treatment but the addition of carbon enables a wide range of hardness and strength. In Austenitic and Ferritic stainless steels a high carbon content is undesirable, especially for welding due to the threat of carbide precipitation.

Manganese (Mn): Manganese is added to steel to improve hot working properties and increase strength, toughness and hardenability. Manganese, like nickel, is an Austenite forming element and has been used as a substitute for nickel in the AISI200 Series of Austenitic Stainless Steels, e.g. AISI 202 as a substitute for AISI 304. Chromium (Cr): Chromium is added to steel to increase resistance to oxidation. This resistance increases as more chromium is added. 'Stainless Steels have a minimum of 10.5% Chromium (traditionally 11 or 12%). This gives a very marked degree of general corrosion resistance when compared to steels with a lower percentage of Chromium. The corrosion resistance is due to the formation of a self-repairing passive layer of Chromium Oxide on the surface of the stainless steel. Nickel (Ni): Nickel is added in large amounts, over about 8%, to high Chromium stainless steels to form the most important class of corrosion and heat resisting steels.

These are the Austenitic stainless steels, typified by 18-8 (304/1.4301), where the tendency of Nickel to form Austenite is responsible for a great toughness (impact strength) and high strength at both high and low temperatures. Nickel also greatly improves resistance to oxidation and corrosion. Molybdenum (Mo): Molybdenum, when added to chromium-nickel austenitic steels, improves resistance to pitting and crevice corrosion especially in chlorides and sulphur containing environments. Nitrogen (N): Nitrogen has the effect of increasing the Austenite stability of stainless steels and is, as in the case of Nickel, an Austenite forming element. Yield strength is greatly improved when nitrogen is added to stainless steels as is resistance to pitting corrrosion. Copper (Cu): Copper is normally present in stainless steel as a residual element. However, it is added to a few alloys to produce precipitation hardening properties or to enhance corrosion resistance particularly in sea water environments and sulphuric acid. Titanium (Ti): Ttitanium is added for carbide stabilization especially when the material is to be welded.

It combines with carbon to form titanium carbides, which are quite stable and hard lo dissolve in steel, which tends to minimise the occurrence of inter-granular corrosion. Adding approximately 0.25 / 0.60% titanium causes the carbon to combine with titanium in preference to chromium, preventing a tie-up of corrosion-resisting chromium as inter-granular carbides and the accompanying loss of corrosion resistance at the grain boundaries. However, the use of titanium has gradually decreased over recent years due to the ability of steelmakers to deliver stainless steels with very low carbon contents that are readily weldable without stabilisation. Phosphorus (P): Phosphorus is usually added with sulphur, to improve machinability. The Phosphorus present in Austenitic stainless steels increases strength. However, it has a detrimental effect on corrosion resistance and increases the tendency of the material to crack during welding. Sulphur (S): When added in small amounts Sulphur improves machinability. However, like Phosphorous it has a detrimental effect on corrosion resistance and weldability. Selenium (Se): Selenium was previously used as an addition to improve machinability.

Niobium / Colombium (Nb): Niobium is added to steel in order to stabilise carbon, and, as such, performs in the same way as described for Titanium. Niobium also has the effect of strengthening steels and alloys for high temperature service. SiIicon (Si): Silicon is used as a deoxidising (killing) agent in the melting of steel and as a result most steels contain a small percentage of Silicon. Cobalt (Co): Cobalt becomes highly radioactive when exposed to the intense radiation of nuclear reactors, and, as a result, any stainless steel that is in nuclear service will have a Cobalt restriction, usually approximately 0.2% maximum. This problem is emphasized because there is normally a residual Cobalt content in the Nickel used in producing Austenitic stainless steels. Calcium (Ca): Small additions are used to improve machiniability, without the detrimental effects on other properties caused by Sulphur, Phosphorus and Selenium. GCSE CHEMISTRY - Alloys of Iron - Steel - Low Carbon Carbon Steel - Stainless Steel - Titanium Steel - GCSE SCIENCE. are steel, manganese steel, stainless steel and titanium steel. Steel is a mixture of iron and carbon.

The amount of carbon may range from 0·1% to 1·5% giving steels of different properties. The exact composition of the steel can be monitored by atomic emission spectroscopy during production. Over half of the steel used each year in the UK is recycled . Low carbon steel (less than 0·25% carbon) is called mild steel. Mild steel is cheap, strong and easily shaped. It is the main metal for construction and is used to make bridges, buildings, ships and vehicles. High carbon steel (more than 0·5% carbon) is stronger than mild steel but it is more brittle. High carbon steel is used to make tools and cutters. Steel has the disadvantage of needing a protective coating (for example paint) or it will react with oxygen in the air and rust. Rusting is the reverse of the process in the blast furnace . Manganese steel is an alloy of iron (84%), manganese (15%) and carbon (1%). Manganese steel is extremely hard and is used for railway points and dredging equipment. Stainless steel is an alloy of iron (80%), chromium (15%), nickel (4%) and carbon (0·5 to 1%).

Stainless steel is strong and hard, with a very high resistance to corrosion (due to chromium). It is used for cookware, cutlery and industrial chemical plant. Titanium steel may contain 0·5 to 2% titanium with varying amounts of other metals including chromium, nickel and vanadium. Titanium steel is very hard and finds uses in aircraft and armour plating. - BIR - Bureau of International Recycling All Market Reports Materials Stainless steel is an iron alloy that contains nickel and chromium to protect it against corrosion and rust. Also known as inox steel, this material is remarkably strong and resistant to high temperatures providing optimum performance under severe environmental and chemical conditions. Stainless steel’s inherent physical properties make it ideal for use in the construction, automotive and transportation sectors. Its versatility also makes it a popular material in household items such as kitchen appliances and cutlery. The demand for stainless steel has doubled in the last ten years, with production increasing to more than 25 million tonnes a year. In this context, the recycling industry has become a vital player in providing a stable supply of quality secondary raw material.

Besides nickel and chromium, other major alloying elements used in combination with steel include; molybdenum, titanium, tungsten and vanadium. These metals are scarce and only available in very few parts of the word, which makes extraction costly and difficult. Recycling is therefore essential to avoid depleting the planet’s natural resources. Recycling Processes Most of these special alloys are very similar in appearance. Sophisticated identification technology, including X-ray spectrometry, are used to separate and prepare each type. Recycling stainless steel is a similar process to the one used for other ferrous metals. Baled metal ready for melting Trimming shears being used to separate one type of metal from another Sorting: Because many forms of stainless steel are non magnetic, this metal cannot be easily separated from other recyclables in a recycling facility with magnetic belts. Baling: Stainless steel products are compacted into large blocks to improve ease of handling and transport. Shearing: Hydraulic machinery capable of exerting enormous pressure is used to cut thick heavy stainless steel into smaller pieces. Media separation: Shredders incorporate rotating magnetic drums to separate ferrous metals from other materials. Further separation is achieved using electrical currents, high-pressure air flow and liquid floating systems.

Melting: The recovered materials are melted together in a furnace. This process is determined by the level of purity necessary for the future applications of the secondary raw material. The melted stainless steel is then poured into casters and shaped into ingots or slabs. Later on, they can be rolled into flat sheets that are used to manufacture new products. Applications Stainless steel is 100% recyclable and loses none of its original physical properties in the process. The most common applications include: Construction: The excellent corrosion resistance, strength and malleability allow for the construction of attractive, low maintenance and durable curtain walls and roofs. Food storage and production: Stainless steel resists bacteria colonisation, does not alter the taste of foods, and is easily cleaned and sterilised. Transport: Passenger rail cars of today's high-speed trains are often constructed of stainless steel which offers structural strength and improved crash protection. Healthcare: Most surgical instruments are made of stainless steel because of its strength and resistance to regular cleaning and sterilisation. Household: Stainless steel has been traditionally used in cutlery, cookware and appliances.

Recycling Facts Recycling one tonne of steel saves 1,100 kilograms of iron ore, 630 kilograms of coal, and 55 kilograms of limestone. An average stainless steel object is composed of about 60% recycled material. Approximately 90% of end-of-life stainless steel is collected and recycled into new products. Our Experts For further information on technical issues, contact our experts working on the Stainless & Special Alloys Commodity Committee: Iron and steel - Introduction to their science, properties, uses Iron and steel Tweet by Chris Woodford . Last updated: July 14, 2016. Think of the greatest structures of the 19th century—the Eiffel Tower, the Capitol, the Statue of Liberty—and you'll be thinking of iron. The fourth most common element in Earth's crust, iron has been in widespread use now for about 6000 years. Hugely versatile, and one of the strongest and cheapest metals , it became an important building block of the Industrial Revolution, but it's also an essential element in plant and animal life.

Combined with varying (but tiny) amounts of carbon, iron makes a much stronger material called steel, used in a huge range of human-made objects, from cutlery to warships , skyscrapers, and space rockets. Let's take a closer look at these two superb materials and find out what makes them so popular! Photo: The world's first cast-iron bridge, after which the village of Ironbridge in Shropshire, England was named. It was built across the River Severn by Abraham Darby III in 1779 using some 384 tons of iron. You can read more about its history and construction on the official Ironbridge website. Photo by Jason Smith courtesy of Wikimedia Commons . What is iron like? Photo: A sample of iron from a meteorite (next to a pen for scale). From the mineral collection of Brigham Young University Department of Geology, Provo, Utah. Photograph by Andrew Silver courtesy of US Geological Survey Photographic Library . You might think of iron as a hard, strong metal tough enough to support bridges and buildings , but that's not pure iron. What you're thinking of is alloys of iron combined with carbon and other elements. Pure iron is a different matter altogether.

Consider its physical properties (how it behaves by itself) and its chemical properties (how it combines and reacts with other elements and compounds). Physical properties Pure iron is a silvery-white metal that's easy to work and shape and it's just soft enough to cut through (with quite a bit of difficulty) using a knife. You can hammer iron into sheets and draw it into wires. Like most metals, iron conducts electricity and heat very well and it's very easy to magnetize . Chemical properties The reason we so rarely see pure iron is that it combines readily with oxygen. Indeed, iron's major drawback as a construction material is that it reacts with moist air (in a process called corrosion) to form the flaky, reddish-brown oxide we call rust. Iron reacts in lots of other ways too—with elements ranging from carbon, sulfur, and silicon to halogens such as chlorine. Broadly, iron's compounds can be divided into two groups known as ferrous and ferric (the old names) or iron (II) and iron (III); you can always substitute "iron(II)" for "ferrous" and "iron(III)" for "ferric" in compound names.

In iron (II) compounds, iron has a valency (chemical combining ability) of +2. Examples include iron(II) oxide (FeO), a pigment (coloring chemical); iron (II) chloride (FeCl2), used in medicine as "tincture of iron"; and an important dyeing chemical called iron (II) sulfate (FeSO4). In iron (III) compounds, iron's valency is +3. Examples include iron (III) oxide (Fe2O3), used as the magnetic material in things like cassette tapes and computer hard drives and also as a paint pigment; and iron (III) chloride (FeCl3), used to manufacture many industrial chemicals. Sometimes iron (II) and iron (III) are present in the same compound. A paint pigment called Prussian blue is actually a complex compound of iron (II), iron (III), and cyanide with the chemical formula Fe4[Fe(CN)6]3. Photo: Iron in action: Chances are you're using magnetic iron (III) oxide right this minute in your computer's hard drive. Where does iron come from? Photo: Iron is essential for a healthy diet. That's why it's packed into many breakfast cereals.

A 100g portion of these cornflakes provides 14.0mg of iron—enough to meet a typical person's needs for one day. This amount of iron is called your recommended daily average or RDA. Here's a great little experiment from Scientific American to extract the iron from your cornflakes . Iron is the second most common metal in Earth's crust, after aluminum , but because it reacts so readily with oxygen it's never mined in its pure form (though meteorites are occasionally discovered that contain samples of pure iron). Like aluminum, most iron "locked" inside Earth exists in the form of oxides (compounds of iron and oxygen). Iron oxides exist in seven main ores (raw, rocky minerals mined from Earth): Hematite (the most plentiful) Siderite Taconite (a combination of hematite and magnetite). Different ores contain different amounts of iron. Hematite and magnetite have about 70 percent iron, limonite has about 60 percent, pyrite and siderite have 50 percent, while taconite has only 30 percent.

Using a combination of both deep mining (under the ground) and opencast mining (on the surface), the world produces approximately 1000 million tons of iron ore each year, with China responsible for just over half of it. Which countries produce the world's iron? Chart shows estimated figures for pig iron for 2015. In the United States, four companies currently produce pig iron in 11 different locations. Source: US Geological Survey, Mineral Commodity Summaries, January 2016. Types of iron Pure iron is too soft and reactive to be of much real use, so most of the "iron" we tend to use for everyday purposes is actually in the form of iron alloys : iron mixed with other elements (especially carbon) to make stronger, more resilient forms of the metal including steel. Broadly speaking, steel is an alloy of iron that contains up to about 2 percent carbon, while other forms of iron contain about 2–4 percent carbon. In fact, there are thousands of different kinds of iron and steel, all containing slightly different amounts of other alloying elements. Pig iron Basic raw iron is called pig iron because it's produced in the form of chunky molded blocks known as pigs.

Pig iron is made by heating an iron ore (rich in iron oxide) in a blast furnace: an enormous industrial fireplace, shaped like a cylinder, into which huge drafts of hot air are introduced in regular "blasts". Blast furnaces are often spectacularly huge: some are 30–60m (100–200ft) high, hold dozens of trucks worth of raw materials, and often operate continuously for years at a time without being switched off or cooled down. Inside the furnace, the iron ore reacts chemically with coke (a carbon-rich form of coal) and limestone. The coke "steals" the oxygen from the iron oxide (in a chemical process called reduction), leaving behind a relatively pure liquid iron, while the limestone helps to remove the other parts of the rocky ore (including clay, sand, and small stones), which form a waste slurry known as slag. The iron made in a blast furnace is an alloy containing about 90–95 percent iron, 3–4 percent carbon, and traces of other elements such as silicon, manganese, and phosphorus, depending on the ore used.

Pig iron is much harder than 100 percent pure iron, but still too weak for most everyday purposes. Cast iron Cast iron is simply liquid iron that has been cast: poured into a mold and allowed to cool and harden to form a finished structural shape, such as a pipe, a gear , or a big girder for an iron bridge . Pig iron is actually a very basic form of cast iron, but it's molded only very crudely because it's typically melted down to make steel. The high carbon content of cast iron (the same as pig iron—roughly 3–4 percent) makes it extremely hard and brittle: large crystals of carbon embedded in cast iron stop the crystals of iron from moving about. Cast iron has two big drawbacks: first, because it's hard and brittle, it's virtually impossible to shape, even when heated; second, it rusts relatively easily. It's worth noting that there are actually several different types of cast iron, including white and gray cast irons (named for the coloring of the finished product caused by the way the carbon inside it behaves).

Photo: One of the world's most famous iron buildings, the Capitol in Washington, DC has a dome made of 8,909,200 pounds of cast iron! Photo by courtesy of The Architect of the Capitol . Wrought iron Cast iron assumes its finished shape the moment the liquid iron alloy cools down in the mold. Wrought iron is a very different material made by mixing liquid iron with some slag. The result is an iron alloy with a much lower carbon content. Wrought iron is softer than cast iron and much less tough, so you can heat it up to shape it relatively easily, and it's also much less prone to rusting. However, relatively little wrought iron is now produced commercially, since most of the objects originally produced from it are now made from steel, which is both cheaper and generally of more consistent quality. Wrought iron is what people used to use before they really mastered making steel in large quantities in the mid-19th century. Types of steel Strictly speaking, steel is just another type of iron alloy, but it has a much lower carbon content than cast and wrought iron and other metals are often added to give it extra properties.

Steel is such an amazingly useful material that we tend to talk about it as though it were a metal in its own right—a kind of sleeker, more modern "son of iron" that's taken over the family firm! It's important to remember two things, however. First, steel is still essentially (and overwhelmingly) made from iron. Second, there are literally thousands of different types of steel, many of them precisely designed by materials scientists to perform a particular job under very exacting conditions. When we talk about "steel", we usually mean "steels"; broadly speaking, steels fall into four groups: carbon steels, alloy steels, tool steels, and stainless steels. These names can be confusing, because all alloy steels contain carbon (as do all other steels), all carbon steels are also alloys, and both tool steels and stainless steels are alloys too. Carbon steels The vast majority of steel produced each day (around 80–90 percent) is what we call carbon steel, though it contains only a tiny amount of carbon—sometimes much less than 1 percent. In other words, carbon steel is just basic, ordinary steel.

Steels with about 1–2 percent carbon are called (not surprisingly) high-carbon steels and, like cast-iron, they tend to be hard and brittle; steels with less than 1 percent carbon are known as low-carbon steels and like wrought iron, are softer and easier to shape. A huge range of different everyday items are made carbon steels, from car bodies and warship hulls to steel cans and engine parts. Alloy steels As well as iron and carbon, alloy steels contain one or more other elements, such as chromium , copper , manganese, nickel , silicon, or vanadium. In alloy steels, it's these extra elements that make the difference and provide some important additional feature or improved property compared to ordinary carbon steels. Alloy steels are generally stronger, harder, tougher, and more durable than carbon steels. Tool steels Tool steels are especially hard alloy steels used to make tools, dies, and machine parts. They're made from iron and carbon with added elements such as nickel, molybdenum, or tungsten to give extra hardness and resistance to wear.

Tool steels are also toughened up by a process called tempering, in which steel is first heated to a high temperature, then cooled very quickly, then heated again to a lower temperature. Stainless steels The steel you probably see most often is stainless steel—used in household cutlery, scissors, and medical instruments. Stainless steels contain a high proportion of chromium and nickel , are very resistant to corrosion and other chemical reactions, and are easy to clean, polish, and sterilize. Making steel There are three main stages involved in making a steel product. First, you make the steel from iron. Second, you treat the steel to improve its properties (perhaps by tempering it or plating it with another metal). Finally, you roll or otherwise shape the steel into the finished product. Making steel from iron Most steel is made from pig iron (remember: that's an iron alloy containing up to 4 percent carbon) by one of several different processes designed to remove some of the carbon and (optionally) substitute one or more other elements.

The three main steelmaking processes are: Basic oxygen process (BOP): The steel is made in a giant egg-shaped container, open at the top, called a basic oxygen furnace, which is similar to an ordinary blast furnace, only it can rotate to one side to pour off the finished metal. The air draft used in a blast furnace is replaced with an injection of pure oxygen through a pipe called a lance. The basic idea is based on the Bessemer process developed by Sir Henry Bessemer in the 1850s. Open-hearth process (also called the regenerative open hearth): A bit like a giant fireplace in which pig iron, scrap steel, and iron ore are burned with limestone until they fuse together. More pig iron is added, the unwanted carbon combines with oxygen, the impurities are removed as slag and the iron turns to molten steel. Skilled workers sample the steel and continue the process until the iron has exactly the right carbon content to make a particular type of steel. Electric-furnace process: You don't cook your dinner with an open fire, so why make steel in such a primitive way?

That's the thinking behind the electric furnace, which uses electric arcs (effectively giant sparks) to melt pig iron or scrap steel. Since they're much more controllable, electric furnaces are generally used to make higher-specification alloy, carbon, and tool steels. Photo: Making steel for weaponry with the three-ton electric arc furnace at Rock Island Arsenal. Photo by Tony Lopez courtesy of Defense Imagery. Which countries produce the world's raw steel? Approximately 1.65 billion metric tons of steel are made worldwide each year. This chart shows estimated worldwide raw steel production figures for 2015. In the United States, there were 110 "minimill" steel plants in operation at the start of 2016 (down from 113 a year earlier) making a total of about 110 million tons of steel (slightly down from 114 million tons in 2015). Indiana (27 percent), Ohio (13 percent), Michigan (6 percent), and Pennsylvania (5 percent) together produce about half of all US steel. Source: US Geological Survey, Mineral Commodity Summaries, January 2016.

Making steel products Liquid steel made by one of these processes is cast into huge bars called ingots, each of which weighs anything from a couple of tons (in typical steel plants) to hundreds of tons (in really big plants making giant steel objects). The ingots are rolled and pressed to make three types of basic steel "building blocks" known as blooms (giant bars with square ends), slabs (blooms with rectangular ends), and billets (longer than blooms but with smaller square ends). These blocks are then shaped and worked to make all kinds of final steel products. The basic shaping process usually involves hot rolling (for example, reheating blooms and then rolling them over and over again to make them thinner). Girders are made by rolling steel then forcing it through dies or milling machines to make such things as beams for buildings and railroad tracks. Rollers that are very close together can be used to squeeze steel into extremely thin sheets. Pipes are made by wrapping sheets round into circles then forcing the two edges together so they fuse under pressure where they join. Shaped steel can be further treated in all kinds of ways.

For example, "tins" for food containers (which are mostly steel) are made by electroplating steel sheets with molten tin using the process of electrolysis (the reverse of the electro-chemical process that happens in batteries ). Steel that needs to be especially resistant to weathering can be galvanized (dipped into a hot bath of molten zinc so it acquires an overall protective coating). Why is one type of iron and steel harder or softer than another? In all this discussion of iron and steel, you'll have noticed that different types behave almost like completely different materials under different conditions. What makes one form of iron or steel different from another? Why are some very hard and brittle while others are relatively soft and malleable (easy to work)? Peer at the internal structure of iron or steel under an electron microscope and you'll see that the answer largely boils down to how much carbon the iron contains and how it's distributed. Iron and steel consist of grains made of different kinds of iron and carbon, some of which are hard, while others are soft.

When the harder kinds predominate, you get a hard and brittle material; when there are more softer kinds in between, the material can bend and flex so you can work and shape it more easily. ? The compounds inside iron and steel include some or all of the following: Ferrite: Relatively pure iron with tiny amounts of carbon that is soft and easy to shape. Gives iron its magnetic property. Cementite (iron carbide): Iron with much more carbon (and sometimes other elements) that is very hard and brittle. Essentially behaves like a ceramic material. Graphite: Pure carbon crystals, which make iron alloys hard and brittle. Pearlite: A mixture made of alternate layers of ferrite and cementite that looks like mother of pearl under a microscope (hence the name "pearlite"). Austenite: An alloy of iron and carbon present in steel heated to high temperatures. Martensite: Similar to ferrite but much harder. Different types of iron and steel contain different amounts of these ingredients arranged in varying crystalline structures. Making iron alloys or steel by one method or another will change the relative amounts of the ingredients, altering its properties.

Treating steel in different ways after it's made changes its physical properties by altering its internal crystalline structure. For example, heat-treating steel changes austenite inside it into martensite, making its internal structure very much harder. Hammering and rolling steel breaks up crystals of graphite and other impurities lurking inside it, closes up any gaps that could lead to weaknesses, and generally produces a more regular crystalline structure. What is steel used for? Steel is one of the most versatile materials, used in everything from jet engines to surgical instruments and from table knives to machine tools. Major consumers of steel include the automobile and shipbuilding industries, the construction industry, producers of food cans, and manufacturers of electrical appliances. Photo: The inner steel skeleton of a building under construction. Many buildings are "quietly" supported by a secret inner structure like this that becomes invisible once they're complete. A brief history of iron and steel 4000 BCE: Iron is first used for ornaments and decoration, probably in the Middle East. 2500 BCE: Iron is used on a large scale for the first time by the Hittites, in a region now occupied by Turkey and Syria.

1200 BCE: Wrought iron (similar to steel) is developed. 1000 BCE: Iron Age begins: iron is widely used for making tools and weapons in many parts of the world. 200 BCE: Cast-iron objects are produced in China. 300BCE–400CE: First steel furnaces used in Africa, India, and China. 500–1000 CE: Blacksmiths make many important iron goods including weapons, plows, and horseshoes. 700: An efficient iron-making furnace called the Catalan forge is developed in Spain. 1200–1500: Blast furnaces powered by waterwheels become popular. 1709: Abraham Darby first uses coke (a type of coal) to make pig iron in Coalbrookdale in Shropshire in England's Midlands. His grandson, Abraham Darby III, uses cast iron to make a famous iron bridge at a place now called "Ironbridge," widely considered the heart of the English Industrial Revolution. 1856: Henry Bessemer announces his invention of the Bessemer converter, a basic oxygen furnace that can convert iron to steel in very large, commercial quantities.

1861: The brothers William and Frederick Siemens develop the open-hearth furnace 1879: William Siemens invents the electric furnace. 1954: Modern basic oxygen process is invented. Metals On other websites USGS Minerals Information: Iron and steel : Current statistics and other information about US and worldwide iron and steel production. American Iron and Steel Institute : Leading US trade organization. Website contains some simple background information about how we use steel today. Association for Iron & Steel Technology : Quite detailed background, though some sections of the site are for members only. Books General books for older readers Dreams of Iron and Steel by Deborah Cadbury. HarperCollins, 2004. Surveys seven "wonders of the modern world" made possible by iron and steel technology, including the Panama Canal, the London sewers, the Brooklyn Bridge, and the Hoover Dam. Stuff Matters by Mark Miodownik. Penguin, 2014. A friendly introduction to essential everyday materials.

Steel is covering in Chapter 1, "Indomitable." BBC - GCSE Bitesize: Iron and steel Next Iron and steel Pure iron is soft and easily shaped because its atoms are arranged in a regular way that lets layers of atoms slide over each other. Pure iron is too soft for many uses. Layers of atoms slide over each other when metals are bent or stretched Iron from the blast furnace is an alloy of about 96 percent iron, with carbon and some other impurities. It is hard, but too brittle for most uses, so most iron from the blast furnace is converted into steel by removing some of the carbon. Steel Carbon is removed from molten iron by blowing oxygen into it. The oxygen reacts with the carbon, producing carbon monoxide and carbon dioxide, which escape from the molten metal. Enough oxygen is used to achieve steel with the desired carbon content. Other metals are often added, such as vanadium and chromium, to produce alloysalloy: An alloy is a compound of two or more elements, at least one of which is a metal. with properties suited to specific uses. There are many different types of steel, depending on the other elements mixed with the iron.

A summary of the properties of some different steels Type of steel Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys Nickel Alloy Manufacturing Process Nickel has been used in alloys that date back to the dawn of civilization. Nickel in elemental form or alloyed with other metals and materials has made significant contributions to our present-day society and promises to continue to supply materials for an even more demanding future. Nickel is a versatile element and will alloy with most metals. Complete solid solubility exists between nickel and copper. Wide solubility ranges between iron, chromium, and nickel make possible many alloy combinations. Nickel Alloys - Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys and Magnetic Alloys Topics Covered Magnetic Alloys Stainless steels The majority of the stainless steels contain 8-10% nickel. In all cases it is the combination of chromium with the nickel that does the job. Stainless steels are also useful as fire retardant materials since they retain their strength to higher temperatures than structural steel. The most common stainless steel is the 304 grade with 8% nickel and 18% chromium and the balance iron.

This is used for such common items as spoons and forks, saucepans and kitchen sinks. Where extra corrosion resistance is required, such as for roofing in marine applications, type 316 is used. This has about the same amount of nickel and chromium as 304 but with 3% of molybdenum added. The balance is again iron. There are many other stainless steels to cover the wide spectrum of demands of engineers and architects such as nickel plated steel ( NPS ). Nickel Copper Alloys These nickel copper alloys are sometimes referred to as MONEL or NICORROS and contain nickel with copper and small amounts of iron and manganese. A typical nickel copper alloy is the 400 grade ( UNS N04400 ). This nickel copper alloys contains 63% nickel minimum, 28-34% copper, and a maximum of 2% manganese and 2.5% iron. There are also a small number of impurities kept at limited values to ensure the metal's properties are not harmed. These nickel copper alloys are used where a higher strength is required compared to pure nickel.

Nickel copper alloys have a wider range of environments where they resist corrosion but in some specialised applications, such as strong alkali contaminant, nickel or commercially pure nickel would be superior. Nickel copper alloys find wide application in oil refining and marine applications where long corrosion-free life is required. Because of good thermal conductivity of nickel copper alloys, they are frequently are used for heat exchangers where sea water is one of the fluids concerned. Nickel Chromium Base Alloys These nickel chromium base alloys are used extensively in applications where heat resistance and/or corrosion resistance is required. In some members of the group, where conditions are less demanding, some nickel is replaced by iron to decrease the overall cost. Metals fail at high temperatures by both oxidation (scaling) and through a loss in strength. Alloys in this class are designed to resist failure from both of these mechanisms. Nickel alloys are not suitable for high temperature sulphur rich environments. Where corrosion resistance is significant, molybdenum is used as an alloying addition in nickel chromium based alloys. This group of alloys are frequently sold under trade name specifications but most are listed in the Unified Numbering System.

Common trade names are HASTELLOY , INCOLOY , INCONEL , NICROFER , NICROM and NIMONIC . The more recentnickel chromium base alloys in these groups also have a wide range of ancillary elements added to give special properties - some of these can be quite complicated and require very close control over composition and heat treatment. Table 1. Compositions of some common nickel alloys. UNS No 382 170 This list is far from exhaustive and enquiries to nickel alloy manufacturars should be made for specialised high temperature or corrosive situations. All metals 'creep' under stress at high temperature and in their manufactured form, components may deform. This deformation could cause failure. Nickel alloys have higher strength and longer life at elevated temperature than most alloys. This makes them ideal for such parts as blades and disks in gas turbine engines. The designer however, must determine the expected life of each component and use the appropriate creep and rupture strength in the design. Low Expansion Alloys There are a group of nickel-iron controlled expansion alloys where the expansion coefficient is low and constant over a range of temperatures.

These nickel iron low expansion alloys are used extensively where changes in mechanical properties with temperature could be a problem, such as in precision springs. These nickel iron alloys are also used where a metal/glass seal is required called as Glass Sealing Alloys . One example is the alloy containing 48% nickel and the balance iron ( UNS K94800 ). This alloy has the following expansion coefficients: 20-100ï¿½C: 8.5 x 10-6m/m.ï¿½C 20-400ï¿½C: 8.3-9.3 x 10-6m/m.ï¿½C This nickel iron alloy has an expansion co-efficient designed to match that of soda-lime and soft lead glasses and thus provides a sound glass/metal seal that will not crack because of differential expansion between the two materials. Another such seal is provided by dumet wires for lamps Magnetic Alloys There is a requirement for materials with high magnetic permeability to minimise the power requirements to generate a strong magnetic field, such as that required in tape recorder heads and for magnetic shielding around precision cathode ray display devices.

These high permeability materials are complex alloys based on nickel with a range of composition possibilities. A typical composition could be: 70-80% nickel with small amounts of molybdenum and/or copper and the balance iron. This alloy would be expected to have a maximum relative permeability of between 50,000 and 100,000. Common trade names of this group are MU-METAL and PERMALLOY . There is also a requirement for materials with a constant permeability over a range of magnetic flux densities. This is required in telephone equipment and electrical fitters where a variation in permeability would result in distortion. These alloys are generally known as the PERMINVAR alloys and have compositions ranging around 45% nickel, 30% iron and 25% cobalt. Trade Names and Owners of Nickel Alloys HASTELLOY is a registered trade name of Haynes Intl. INCOLOY, INCONEL, MONEL and NIMONIC are registered trade names of the INCO family of companies. INVAR is a registered trademark of Imphy S.A.

MU-METAL is a registered trademark of Telcon Metals Ltd NICORROS and NICROFER are registered tradenames of Krupp UM GmbH Source: Abstracted from Handbook of Engineering Materials, 5th Edition. For more information on this source please visit The Institute of Materials Engineering Australasia . Content Copyright of Respective Copyright Holders.

Question: Which metal is alloyed with iron to make Stainless Steel?
Answer: CHROMIUM